I think that people are reading this as if I’m saying this is the only preparation needed. What I’m saying is that after you have a solid understanding of the blueprint topics and are ready to move onto the full scale labs that doing 30 full scale labs by repeating the same 6 labs 5 times each is better for some people than doing 30 totally different full scale labs.

I had the right idea for this task, but I boned it up. IE used an aggregate-address on sw1 to ensure reachability to all networks advertised by the backbone routers. They have a short writeup to explain their method.

I guess that I can take solace in the fact that I was able to find my mistake. I just barely missed going down a deep rabbit hole chasing bridging options.

4.3 RIPv2

I initially thought that there was an error in the IE lab because although r6 was shown as running RIP on the protocol diagram, there was no mention of r6 in the task. That’s because r6 is bridging the 54.1.10.0/24 network. I turned off ip routing in task 4.1 so I wouldn’t be able to configure RIP on r6:

r6(config)#router rip
IP routing not enabled

This means that we should be able to see the routes from bb1(54.1.10.254) on r4:

Four points of mutual redistribution. Ugh. The first two points are no worry (discontiguous RIP). The other two are dangerous though. I’ll work on those in task 4.11

4.11 Redistribution Loop Prevention

“Ensure that EIGRP extenal routes that are redistributed into OSPF on r1 and r2 do not get redistributed back into EIGRP.”
“Use AD to accomplish this.”

Here is a (simplified) view of the the two network redistribution points on r1 and r2:
————(D)r1(O)———–r4(R<->D)—r5(D) (O)r3—(O<->R)sw1
————(D)r2(O)———–
If we do mutual redistribution between EIGRP and OSPF on r1 and r2 we’re going to have problems with D EX routes (AD of 170) being reflected back into the EIGRP domain. We’re given the method for preventing this.

You need to change the RIP distance or SW1 sees the routes learnt from BB3 as OSPF external routes which it uses over the correct RIP routes. if you check the routing table on SW1, the next hop for all the BB3 subnets is R3. This is resolved by changing the AD [router rip – distance 109].